JPH02249530A - Action current display method - Google Patents

Abstract

PURPOSE:To ensure a precise diagnosis, and safe remedy and surgery by obtaining a minimum value of root means square errors between several simulation data which are obtained by collecting action currents imagined at an arbitrary position in an organism, and actual data, and then by superposing the minimum value with a tomographic image so as to display a mark indicating the action current. CONSTITUTION:Magnetic fields which are produced by currents applied to small coils 3a, 3b, 3c attached to three feature points on the head of a person to be diagnosed, are detected by a multichannel SQUID sensor 1, and adjustment is made so as to make thus obtained positional data coincident with positional data of the small coils on a tomographic image so as to grasp the head position. Magnetic field distribution data B1, B2, B3...Bn are actually measured by the SQUID sensor 1 having n channels, and the root means square errors between these magnetic field distribution data and individual simulation data B1ijk, B2ijk, B3ijk...Bnijk are calculated. Further, a minimum value among the root means square errors is obtained. Thus obtained tomographic image is displayed on a display, and a mark indicating a current dipole Mijk(obj) relating to an action current which satisfied the condition concerning a position Pi(obj), a size and direction is displayed, being superposed with the tomographic image.

Description

[Detailed Description of the Invention] A. Industrial Application Field This invention is applicable to MRr equipment (nuclear magnetic resonance imaging bag U,
B. Conventional technology concerning a method of superimposing current dipoles related to biological activity currents on a tomographic image obtained by a T device, etc. When a stimulus is given to a living body, the polarization formed across the cell membrane is broken and the biological activity currents are flows. This biological activity current appears in the brain and heart, and is called an electroencephalogram.

Recorded as an electrocardiogram. Furthermore, magnetic fields generated by biological activity currents are recorded as magnetoencephalograms and magnetocardiograms.

In recent years, 5Q has been used as a device to measure minute magnetic fields inside living organisms.
A sensor using a UID (superconducting quantum interferometer) has been developed.

By placing this sensor on the outside of the head, it is possible to non-invasively measure minute magnetic fields caused by biological activity currents generated within the brain. When such measurements are performed at a large number of measurement points and the obtained data and the interpolated data are plotted on a developed diagram of the head surface, an equal magnetic field map as shown in FIG. 7 is obtained. Note that in the case of potential measurement, a similar equipotential map can be obtained.

The isomagnetic field map shown in Figure 7 shows one highest level of magnetic field strength (peaks shown by solid lines) and one lowest level (troughs shown by broken lines). corresponds to the case. In this case, when the current dipole is single, the Biot-Savart law can be applied to estimate the position, direction, and magnitude of the current dipole in the brain, and the current dipole as shown by the arrow in the figure Dipoles can be localized.

C3 Problems to be Solved by the Invention However, in many cases, the patterns of equipotential maps and equipotential maps are complex, and many sets of highest and lowest levels appear, so the Biot-Sanoir law cannot be applied. In other words, although it is possible to grasp the overall general trend of magnetic field and potential distribution using equipotential maps and equipotential maps, the reality is that it is not possible to localize the locations where current dipoles occur. It is.

Furthermore, even if it is possible to localize the current dipoles as in the case of Figure 7, it is only possible to know the relative positional relationship on the equipotential field map or equipotential map. There was a problem in that it was not possible to directly visually grasp the actual position in the brain.

This invention was made in view of these circumstances, and it is possible to localize current dipoles related to biological activity currents even under conditions where the Biot-Savart law cannot be applied. The purpose is to make it possible to visually and directly grasp the actual position in the living body.

08 Means for Solving the Problems In order to achieve the above object, the present invention has the following configuration.

That is, in the biological activity current display method of the present invention, a large amount of simulation data of the magnetic field or potential distribution of the biological activity current at a hypothetical arbitrary position in the living body is collected in advance, and the data is actually measured on the subject. Calculate the root mean square error between the actual measurement data of the magnetic field or potential distribution and the above-mentioned simulation data, find the minimum root mean square error among these root mean square errors, and calculate 1 corresponding to this minimum root mean square error. The present invention is characterized in that a mark indicating a biological activity current is displayed superimposed on a tomographic image at a position corresponding to two simulation data.

88 action The effects of the configuration of this invention are as follows.

That is, since one simulation data corresponding to the minimum value of the root mean square error between a large number of simulation data and actual measurement data has data at the position closest to the generation site of the biological activity current corresponding to the actual measurement data, Even under conditions where the Biot-Savart law cannot be applied, current dipoles related to biological activity currents can be localized.

Since a mark indicating the biological activity current is displayed superimposed on the tomographic image at the position of the simulation data with the minimum root mean square error value, it is possible to visually and directly determine the actual position of the current dipole in the living body. It becomes possible to understand.

F. Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

■ Using a multi-channel 5QtJID sensor that can measure in-vivo micromagnetic fields at multiple points simultaneously, data on the magnetic field distribution formed by a virtual current dipole in the brain is collected in advance. The collection is done as follows.

As shown in Fig. 1, virtual current dipoles M, Jk of arbitrary magnitude Ij and arbitrary direction φ are placed at an arbitrary position Pi (X+,)'i+Zr) expressed in the orthogonal coordinate system. Suppose.

Bljjk is the data obtained by measuring the magnetic field due to the current dipole MiJk for each channel, where n is the number of channels of the multi-channel 5QUID sensor 1.

B□jk+ B□0...B aijk, and the simulation data of this magnetic field distribution is σ! It is stored as Jk in file 2 as shown in Figure 2.

To explain this simulation data σink in more detail: ■ The position Pt and the size T are the same, and k(=1.2
...W) as a parameter, the direction φ is φ1. φ
2... All simulation data that differ as in φ, ■ The position P and direction φa are the same, and j (=1.2
...V) as a parameter, the size I.

All simulation data with different values such as T+, It...Iv, ■ Size Ij and direction φ are the same, and 1(-1, 2
...U) as a parameter, position P1 is Pl, P
It consists of all different groups of simulation data, such as l...P.

The number of simulation data σjjk is equal to the number (uXvXk) obtained by multiplying the number of parameters u of i, the number v of parameters of j, and the number W of parameters.

■ As shown in Figure 3, current is passed through small coils 3a, 3b, and 3c attached to three characteristic points on the subject's head (the nasal root, the preauricular notch, and the external occipital prominence). A multi-channel 5QUID sensor 1 detects the magnetic field generated by the small coils 3a and 3b in a coordinate system with this sensor l as a reference.

Obtain position data of 3c.

On the other hand, with respect to the frontal tomographic image and side tomographic image of the head obtained by the MRI device or the Align and overlap. As a result, position data of the small coils on the tomographic image can be obtained.

Then, adjustment is made between the position data so that the position data of the small coil obtained by the sensor 1 and the position data of the small coil on the tomographic image match. As a result, the position of the head in the coordinate system based on sensor 1 can be grasped. (See positional relationship measurement method 1).

(2) Magnetic field distribution data B, Bx, B, . . . B7 are actually measured by the n-channel 5QUID sensor 1 and stored in the file 4 as shown in FIG.

And this measured data B+, Bz, By...
B, l, and one simulation data σ1jk
(=B eye 1.82 eye 1.B, eye,...B ++1j
k) and calculate the root mean square error Δ5.

Σ(Ba+3m Bar) ” Δijk = Σ B,! There are also (uXvXk) root mean square errors Δ1.3.

Next, find the minimum value Δ1j□, I0) of these (uXvXk) root mean square errors Δpositive, 1, and (uXvXk)
Simulation data σ1 corresponding to the minimum value Δm Jk (+ai1) among the simulation data σ
nk(. Determine kjl.

As mentioned above, each simulation data σdirection□ includes the position PL(x+,
Since there is a one-to-one correspondence between y512, size IJ, and direction φ, the minimum value of the root mean square error Δ1k(,,simulation data corresponding to R1, σ1.□.,1.
Unique position Pi(., j, (χ,
. bjl+yi(.kJl+Z□.,j,), unique size r j fobjl, unique direction φ1゜bj)
corresponds.

At this point I P + (.5C, the size Ij (.b
jl, current dipole MB with direction φk(·IJI, (.

bj) is a current dipole corresponding to the measured magnetic field distribution data.

■ A tomographic image obtained by an MRI device or an X-ray CT device is displayed on a display, and in a state where it is superimposed on the tomographic image, the above-mentioned size W P 1 (.
. bJl, direction φ□. A mark indicating the current dipole M, jk (.bjl) related to the biological activity current that satisfies the condition of bj) is displayed.

There are several ways to display marks indicating this current dipole as follows.

(a) Suppose that the slice plane displayed on the slice tomographic image is along the xy plane. As shown in FIG. 5, a slice plane corresponding to Zl(.5,) is selected from among a plurality of slice planes in two directions, and its slice tomographic image 5 is displayed on the display.

Then, coordinate values (X2.., 4..) are obtained on the x-y plane.

At the position of yHobjl
The size and direction φ projected onto the y-plane. bi>, an arrow mark 6 indicating the current dipole M + jk (0bjl) is displayed superimposed on the slice tomographic image 5. Note that the mark 6 may be highlighted with a specific color.

Φ) Display on a three-dimensional tomographic image As shown in FIG. 6, three-dimensional tomographic images 7a and 7b are cut and displayed on a three-dimensional surface display of the cranium.

At 7C, the coordinate value (X l job + 7 i
At the position of (objl +2 straight (., J,), the size I
. objl and the direction φ5 (., C) may be displayed with an arrow mark 6 superimposed.

As described above, current dipoles related to biological activity currents can be localized in a superimposed state on a tomographic image, and biological activity currents can be visually and directly grasped, improving diagnostic accuracy and
Treatment 1: The safety of surgery can be ensured. It is particularly effective in identifying the affected area of focal epilepsy.

In addition, in the field of brain function research, research on how each part of the body corresponds to which part of the brain, and in the field of psychology, research on where alpha waves are most likely to occur in the brain. is also valid.

Note that when it is only necessary to know the position of the current dipole and it is not necessary to indicate the size and direction, the mark 6 may be a dot display instead of an arrow.

Furthermore, if the distance from the skull surface to the current dipole and other numerical values are displayed in a superimposed manner, it is easier to grasp the location of the affected area in the negative layer.

In the above embodiment, the magnetic field generated by the life activity current is measured by the multi-channel 5QUID sensor, but instead of this, the life activity current may be directly measured by potential measurement.

Effect of G1 invention According to this invention, the following effects are exhibited.

In other words, the minimum value of the root mean square error between a large number of simulation data and actual measurement data collected regarding virtual biological activity currents at any position within the body is determined, and the fault is calculated at the position of one simulation data corresponding to the minimum value. A mark indicating the biological activity current is displayed superimposed on the image, and the simulation data corresponding to the above-mentioned minimum value has data at the position closest to the generation site of the biological activity current corresponding to the actual measurement data. From, bio
Even under conditions where Savart's law cannot be applied, biological activity currents can be localized, and the actual location of biological activity currents within a living body can be visually determined by superimposing the display on a tomographic image. As a result, the accuracy of diagnosis and the safety of treatment 2 surgery can be ensured.

[Brief explanation of drawings]

Figures 1 to 6 relate to embodiments of the present invention; Figure 1 is a diagram showing how a virtual current dipole is measured by a multi-channel 5QtJID sensor, and Figure 2 is a diagram showing how the obtained simulation data is stored. Figure 3 is a diagram showing the consistency of the position related to the multi-channel 5QUID sensor and the position related to the tomographic image, Figure 4 is a diagram showing the file storing actual measurement data, and Figure 5 is a diagram showing the file. FIG. 6 is an explanatory diagram of a state in which marks are superimposed and displayed on a slice tomographic image. FIG. 6 is an explanatory diagram of a state in which marks are superimposed and displayed on a three-dimensional tomographic image. Further, FIG. 7 is a diagram showing an equal magnetic field map according to a conventional example. M, j,... Virtual current dipole σijk... Simulation data Δ, C... Root mean square error Δ1jk (sln+... Minimum value of root mean square error 5...
・Slice tomographic image 6...mark indicating biological activity current? a, 7b, 7c...Three-dimensional tomographic image (a) (b)

Claims (1)

[Claims] (1) A large amount of simulation data of the magnetic field or potential distribution of the biological activity current at a hypothetical arbitrary position in the living body is collected in advance, and it is combined with the actual measured data of the magnetic field or potential distribution actually measured for the subject. Calculate the root mean square error with the individual simulation data, find the minimum root mean square error among these large number of root mean square errors, and superimpose it on the tomographic image at the position of one simulation data corresponding to this minimum root mean square error. A biological activity current display method characterized by displaying a mark indicating a biological activity current in a state in which the current is present.